The 16-year-old R&B powerhouse puts up a good fight -- but the Georgia alt-rocker gets lucky with one of the best original songs in the show's 10-year history.

Michael Becker / FOX

Jessica Sanchez and Phillip Phillips duked it out Tuesday night on American Idol's penultimate performance show: in one corner, the 16-year-old powerhouse from Chula Vista, Calif., gave it all she had, starting off strong with an effortless Whitney Houston cover but losing steam on a boring ballad from the show's storehouse of original songs.

Phillips, in the other corner, began on a blah note himself with "Stand By Me" and finished with an electrifying, shockingly good new song called "Home."

On Wednesday, Ryan Seacrest will announce the result, and, at this point, the title could swing either way: Sanchez, the frontrunner who would be the first female victor in what seems like ages, or Phillips, the 21-year-old Georgia-raised pawn shop worker supported by legions of lady admirers and a potentially game-changing Idol-penned single.

The pair each sang three songs: one chosen by show creator Simon Fuller, one favorite from their respective Idol journeys and one original that would become their Idol victory singles should they win.

In round one, Sanchez belted Houston's "I Have Nothing" -- Fuller's pick -- like it was nothing. No big deal. She probably practiced for five minutes, having known the entire song by heart already (all divas study Whitney); for Sanchez, singing is second nature. If there's any argument working against her, it's that she is so good, she's predictable. The perfection thing could get old after a while. Indeed, sometimes it can be more fun to watch performers who are ticking time bombs of unpredictability (see: Ledet, Joshua; Winehouse, Amy).

Fuller selected Ben E. King's "Stand by Me" for Phillips -- a sad song at its core -- and the low-key alt-rocker performed an arrangement that was rather plodding and soulless; but his largely female fan base won't care. Like with his cover of Bob Seger's "We've Got Tonight," Phillips excels when he sings tender, romantic material that speaks directly to women and makes him appear emotionally vulnerable in the process. (See also: Cook, David).

The winner: according to Randy Jackson, the first round went to Sanchez.

And now, for round two: Sanchez performed "The Prayer," and it was soul-stirring and pitch-perfect, showing all the colors of her multi-dimensional voice: the lilting soprano, the rich Beyonce-esque vibrato, the maturity beyond her years.

As for Phillips, he reprised Billy Joel's "Movin' Out" with signature swagger: half imp, half heartthrob, all grit. Meanwhile, the ladies in the audience brandished signs blaring such come-ons as "WE'VE GOT TONIGHT" as well as the life-sized get-well card "PHEEL BETTER PHILLIPS." (Phillips will undergo surgery for kidney problems after the finale. He's a trooper.)

The winner: Jackson called it "even," though Steven Tyler gave his vote to Sanchez.

For round three, the finalists introduced their respective -- and possibly winning -- new singles.

Sanchez's is called "Change Nothing," a forgettable, flavorless power-pop ballad that fell flat in the judges' eyes. Also: Sanchez, a soul singer at heart, seemed to hate it, too.

"I did not love the song, but what I did love is that you made something more out of the song," said Jackson, while Jennifer Lopez cautioned Sanchez: "When you go to make a record ... you have to be able to say to someone, 'this is not me.'"

Phillips, however, hit the jackpot times infinity with his track, "Home." It's hands down the most exciting original Idol song in the show's 10-year history, with a radio-friendly Mumford & Sons-style melody and catchy chorus -- something everyone is gonna like.

Afterward, the judges rose to their feet, clapping furiously as the crowd howled in approval. Tyler looked seriously floored, as if he too could not believe a song like that ever spawned from a reality TV competition.

"I heard a little Paul Simon in there," declared the banshee-voiced Aerosmith frontman. Jackson railed off a number of adjectives such as "perfect," "genius" and "brilliant."

Although Sanchez is widely predicted to win on Wednesday, "Home" could throw a wrench into her prospects. Not only does Phillip already have the unfair advantage of being a "cute boy," now he also has the better song in the competition.

To which we respond: who should take home season 11's trophy -- the wunderkind with the best voice (Sanchez, duh) or the guy with the best song? Should producers give Sanchez another single before it's too late? Anyone else want to play "Home" on continuous loop?